Some IV fluids are in short supply due to higher-than-expected demand and manufacturing issues. But why do IV fluids contain different chemicals? And why can’t they be interchanged when one runs low?
Salt and water are surely relatively cheap (although salt from your kitchen and water from your tap won’t do, you need chemically pure salt and distilled water).
You can make makeshift saline by mixing regular salt in distilled water and autoclaving it at 120°C and 1,2 atm for 30 minutes, but this is not hospital-grade.
Sterile environment and processes, mostly.
Salt and water are surely relatively cheap (although salt from your kitchen and water from your tap won’t do, you need chemically pure salt and distilled water).
You can make makeshift saline by mixing regular salt in distilled water and autoclaving it at 120°C and 1,2 atm for 30 minutes, but this is not hospital-grade.